WO2015078779A1

WO2015078779A1 - Transfer sandwich holder

Info

Publication number: WO2015078779A1
Application number: PCT/EP2014/075264
Authority: WO
Inventors: Nils Stafstrom; Kittur GIRISH; Shekar AMBEPU; Urban Jonsson Axelsson
Original assignee: Ge Healthcare Bio-Sciences Ab
Priority date: 2013-11-28
Filing date: 2014-11-21
Publication date: 2015-06-04

Abstract

A transfer sandwich holder for holding a transfer sandwich is disclosed. The transfer sandwich holder comprising a covering member, at least one rolling member coupled to an end portion of the covering member, and a holding member for holding a transfer sandwich, wherein a rolling member is movably configured with respect to the holding member for applying pressure on the transfer sandwich placed in the holding member, wherein the covering member is arranged with respect to the holding member for opening and closing the transfer sandwich holder.

Description

TRANSFER SANDWICH HOLDER

FIELD OF THE INVENTION

[0001] The subject matter disclosed herein relates to a transfer sandwich holder for electrophoretic separation of samples such as proteins, and more particularly to a transfer sandwich holder with proper handling of a transfer sandwich.

BACKGROUND OF THE INVENTION

[0002] Electrophoresis is an analysis method commonly used that involves migration of charged molecules and particles in a separation medium, usually a gel, when subjected to electrical field between two electrodes. Separation of molecules and particles such as proteins may be by isoelectric point (pi), molecular weight, electric charge, or a combination of these factors. The separation medium is usually placed on a support and two opposing ends of the medium are contacted with an electrode buffer in solution or rigid form. The electrodes may be inserted in vessels containing the electrode buffers. The buffer solutions from both the electrolytic medium and a reservoir for ions to keep the pH and other parameters constant. After separation, the molecules are detected and identified in different ways: e.g. visually by staining the gel or by optical means such as scanning or imaging the stained gel or labeller samples by a laser scanner or the like.

[0003] Electrophoresis process using gel is commonly used for separating

biomolecules such as proteins, peptides, nucleic acids etc. Samples are handled in different types of screening, identifying (cell signaling, expression & purification) or in clinical tests. Protein samples can derivate from e.g. human, mammalian tissue, cell lysates or bacterial, insect or yeast cellular systems. The electrophoretic conditions for different types of molecules are different and have to be adapted in many cases. Thus, both the gel and the buffer solutions must often be chosen for each type of sample.

[0004] The preparation of the electrophoresis process includes several rather laborious steps. A suitable gel is chosen and placed or molded on a support. The gel is contacted with the buffer solutions. A common way is to have a gel slab in a cassette of glass or plastic in contact with the buffer solutions in buffer tanks. For each run the gel has to be placed on the support or the cassette to be prepared. Then the buffer tanks are filled with buffer solutions and the samples are applied on the gel. To go away from the handling of buffer solutions in buffer tanks it has been suggested, in WO 87/04948, to incorporate the buffer substance in a gel material whereby the buffer is obtained in the form of a buffer strip. In addition US6368481 discloses a precast electrophoresis cassette wherein buffer strips are incorporated as an integral part of the cassette.

[0005] Following the electrophoretic separation and in order to detect specific proteins in a given sample, the proteins may be transferred to a membrane (typically nitrocellulose or PVDF), where they are probed (detected) using antibodies specific to the target protein, a process commonly referred to as western blotting or immunoblotting. The primary method for transferring the proteins to the membrane is referred to as electroblotting and uses an electric current to pull proteins from the gel into the membrane. The proteins move from within the gel onto the membrane while maintaining the organization they had within the gel, whereby the proteins are exposed on a thin surface layer for detection. The proteins bind to the surface of the membrane due to its non-specific protein binding properties (i.e. binds all proteins equally well). In order to avoid unspecific binding of probing antibodies, remaining binding sites on the membrane may be blocked. During the probing (detection) process the membrane with the transferred proteins is incubated with specific primary antibody directed towards the protein of interest and secondary antibody e.g. for the protein of interest with a modified antibody which is linked to a reporter enzyme; when exposed to an appropriate substrate this enzyme drives a colorimetric reaction and produces a colour or by fluorescently labeled targets (dyes), that may be detected by a suitable imaging technique.

[0006] Further in the electrophoretic separation the gel and membrane are prepared or arranged in a sandwich form to transfer biomolecules (i.e. samples such as proteins) from gel to the membrane electrophoretically. The gel and membrane arranged in the sandwich form are held in a gel holder or gel cassette firmly. While preparing the sandwich form air gets trapped between the layers. The most common technique used for removing the trapped air is rolling a test tube or pipet on the gel and membrane sandwich. The rolling is done manually by a person. The test tube or pipet may break and result in damaging and improper handling of the gel and membrane sandwich.

[0007] Therefore there is a need for an improved system for removing the trapped air from the gel and membrane sandwich and to ensure its proper handling.

SUMMARY OF THE INVENTION

[0008] The object of the invention is to provide a new transfer sandwich holder, which overcomes one or more drawbacks of the prior art. This is achieved by the transfer sandwich holder as defined in the independent claim.

[0009] One advantage with the transfer sandwich holder is that it facilitates proper handling of the transfer sandwich while removing the trapped air from the transfer sandwich. The transfer sandwich comprises a gel member, a membrane, filter pads and sponge members.

[0010] According to an embodiment there is provided a transfer sandwich holder for holding a transfer sandwich. The transfer sandwich holder comprising a covering member, at least one rolling member coupled to an end portion of the covering member, and a holding member for holding a transfer sandwich, wherein a rolling member is movably configured with respect to the holding member for applying pressure on the transfer sandwich placed in the holding member, wherein the covering member is arranged with respect to the holding member for opening and closing the transfer sandwich holder.

[0011] According to one embodiment the covering member comprises a holder for opening and closing the transfer sandwich holder. The user holds the holder to move the covering member for rolling the rolling member on the transfer sandwich.

[0012] According to one embodiment the holding member comprises multiple guide ways that enable the coupling units to move through the guide ways for enabling the rolling member to roll on the transfer sandwich when the covering member is at a position for opening the transfer sandwich holder.

[0013] According to one embodiment each coupling unit have different configuration to ensure orientation of the covering member while arranged with respect to the holding member. The rolling member is a cylindrical rolling member.

[0014] According to one embodiment each coupling unit have a different

configuration to ensure orientation of the covering member while arranged with respect to the holding member.

[0015] According to one embodiment the holding member comprises one or more snapping members and the covering member comprises one or more snap receivers for engaging one or more snapping members to close the transfer sandwich holder.

[0016] According to one embodiment the transfer sandwich is placed within a transfer sandwich holder. The transfer sandwich holder comprises one or more slots that engage with a snapping member of the one or more snapping members to position the transfer sandwich holder within the holding member.

[0017] A more complete understanding of the present invention, as well as further features and advantages thereof, will be obtained by reference to the following detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a schematic exploded view of an transfer sandwich holder in accordance with an embodiment;

[0019] FIG. 2 is a schematic illustration of an transfer sandwich holder in a rolling position in accordance with an embodiment;

[0020] FIG. 3 is a schematic illustration of a bottom perspective view of a covering member of the transfer sandwich holder; [0021] FIG. 4 is a schematic illustration of a top perspective view of the covering member of the transfer sandwich holder;

[0022] FIG. 5 is a schematic illustration of a top perspective view of a holding member of the transfer sandwich holder;

[0023] FIG. 6 is a schematic illustration of a perspective view of a membrane to be arranged in the holding member of the transfer sandwich holder;

[0024] FIG. 7 is a schematic illustration of a bottom perspective view of the holding member of the transfer sandwich holder;

[0025] FIG. 8 and FIG. 9 are schematic illustrations of a perspective view of the covering member with a rolling member of the transfer sandwich holder in accordance with an embodiment;

[0026] FIG. 10 illustrates the transfer sandwich holder in a rolling position in according with an embodiment;

[0027] FIG. 11 illustrates an exploded perspective view of a transfer sandwich holder in accordance with another embodiment;

[0028] FIG. 12 is a schematic illustration of a slot in a membrane to be arranged in the holding member of the transfer sandwich holder;

[0029] FIG. 13 is a schematic illustration of a stack of the membrane and the gel member indicating detection of disarrangement of the stack in accordance with an embodiment; and

[0030] FIG. 14 is a schematic illustration of a covering member in accordance with another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments that may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized and that logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is, therefore, not to be taken as limiting the scope of the invention.

[0032] As discussed in detail below, embodiments of the invention including a transfer sandwich holder for holding a transfer sandwich is discussed. The transfer sandwich holder comprising a covering member, at least one rolling member coupled to an end portion of the covering member, and a holding member for holding a transfer sandwich, wherein a rolling member is movably configured with respect to the holding member for applying pressure on the transfer sandwich placed in the holding member, wherein the covering member is arranged with respect to the holding member for opening and closing the transfer sandwich holder.

[0033] FIG. 1 is a schematic exploded view of a transfer sandwich holder 100 in accordance with an embodiment. The transfer sandwich holder 100 comprises a covering member 102, one or more rolling members such as a rolling member 104, and a holding member 106. The covering member 102 have an end portion 108 coupled to the one or more rolling members. The covering member 102 have an end 110 and an end 1 12 connected to an end 1 14 and an end 1 16 of the rolling member 104. In an embodiment multiple rolling members may be connected to the covering member 102. The rolling members may have varying diameters. Alternatively all the rolling members may have the same diameter. The diameter of a rolling member may be approximately 11 mm to 12 mm. In an embodiment the diameter of the rolling member may be 1 1.5 mm. Further in another alternative embodiment the rolling members may be of different types and have varying structural configurations. The rolling members may be composed or made of polyoxy methylene, plastic material, or any other polymer material.

[0034] In an embodiment the end 1 10 of the covering member 102 is connected to the end 1 14 using a coupling unit 1 18. The coupling unit 1 18 may be a pin which can be inserted into a hole 120 at the end 1 10. Similarly the end 1 12 of the covering member 102 is connected to the end 1 16 using a coupling unit 122. The coupling unit 122 may be a pin which can be inserted into a hole 124 at the end 1 12. The rolling member 104 is free to rotate with respect to the coupling units 1 18 and 122. In an embodiment the pins are press fitted into the covering member 102. Alternatively in other embodiment different fitting techniques may be used to connect the coupling units to the covering member 102 and the holding member 106. The coupling units 1 18 and 122 facilitate the covering member 102 to be pivotally connected or arranged with respect to the holding member 106. The pivotal arrangement helps in opening and closing of the transfer sandwich holder 100 using the covering member 102. In an embodiment the coupling units 1 18 and 122 may have different configurations for instance different sizes. The coupling unit 1 18 may have a larger size as compared to the coupling unit 122.

According to one embodiment the coupling unit 1 18 may have a larger diameter throughout its length as compared to a diameter of the coupling unit 122. Thus the holes 120 and 124 may have their size accordingly to receive the coupling unit 1 18 and the coupling unit 122 respectively. These differently sized holes and coupling units ensure that the covering member 102 is arranged with respect to the holding member 106 only in a defined orientation. Moreover this also avoids any disarrangement of the holding member 106 and the covering member 102 by a user or any novice user. Further it may be appreciated that the coupling units may have different configurations to ensure correct alignment or arrangement during coupling of the holding member 106 and the covering member 102. The transfer sandwich holder 100 is opened and closed using a holder 126.

[0035] The transfer sandwich holder 100 holds a transfer sandwich 128 such as a transfer sandwich. The transfer sandwich 128 includes multiple layers for separating samples e.g. proteins. The transfer sandwich 128 is positioned between sponge members i.e. a sponge member 130 and a sponge member 132. The sponge member may include a single layer of sponge or multiple layers of sponges. The transfer sandwich 128 includes filter pads i.e. a filter pad 134 and a filter pad 136, a membrane 138 and a gel member 140. The sponge member 130 is positioned in the covering member 102 and the sponge member 132 is positioned in the holding member 106 and remaining layers such as filter pads 134 and 136, the membrane 138 and the gel member 140 are arranged between these sponge members. A membrane is arranged within a rigid frame such as a plastic foil, a laminated foil and so on. For instance a rigid frame 141a is designed to stay attached to the membrane 138 throughout the process steps. The rigid frame 141a is formed of a suitably rigid material to preserve the shape of the membrane 138 and to facilitate handling of the membrane 138 by providing accessible gripping portions outside of the transfer-zone. Further a rigid frame 141b may be arranged supporting the gel member 140. The filters pads 134 and 136 together with the sponge members 130 and 132 facilitate even distribution of pressure on the membrane 138 and the gel member 140 when the transfer sandwich holder 100 is closed. This is explained in more detail in conjunction with FIG. 3 and FIG. 5. The gel member 140 holds the sample e.g. proteins initially that need to be transferred into the membrane 138. All these layers are stacked together in a particular order as schematically shown in FIG. 1 to form the transfer sandwich 128. There can be instances when user does some error while stacking these layers in the transfer sandwich holder 100. An arrangement for avoiding this error is described in detail in conjunction with FIGs.10, 1 1 and 12 below in accordance with an embodiment.

[0036] Now referring back to stacking of layers in the transfer sandwich holder 100, FIG. 2 schematically illustrates the sponge member 130 positioned on a back side 200 of the covering member 102 in accordance to an embodiment. The sponge member 130 is placed on the back side 200 as indicated by arrows 202, 204 and 206. The sponge member 130 is positioned here in order to achieve a uniform pressure over the gel member 140. The back side 200 of the covering member 102 includes a ridge shaped arrangement 208 including multiple ridge members e.g. a ridge member 210 and a ridge member 212. The ridge members firmly hold the sponge member 130 in place and also provide sufficient grip and pressure to hold the transfer sandwich 128 when the covering member 102 closes the transfer sandwich holder 100. In an embodiment the sponge member 130 is placed between the ridge member 210 and the ridge member 212. The ridge members are arranged to construct rectangular patterns to form the ridge shaped arrangement. The rectangular patterns render uniform distribution of pressure onto the transfer sandwich 128 when the transfer sandwich holder 100 is closed. The rectangular patterns formed is according to one embodiment and hence it may be envisioned that different shaped patterns can be formed using the ridge members.

[0037] The covering member 102 also includes a grid arrangement 214 configured along with the ridge shaped arrangement 208 as schematically illustrated in FIG. 2. The grid arrangement 214 has each grid with a hollow configuration. For instance a grid 216 is hollow thereby being visible from an outer side 218 of the covering member 102 as schematically illustrated in FIG. 3. The grid arrangement 214 is provided to allow essentially unrestricted fluidic and electrical contact with the transfer sandwich 128 in order to trigger transfer of the samples from the gel member 140 to the membrane 138. The covering member 102 is positioned proximal to an anode during the transfer process. More specifically the outer side 218 may be facing and positioned close to the anode. In an embodiment the grid arrangement 214 is configured between the ridge shaped arrangement 208 or explaining in another way the ridge shaped arrangement 208 is configured around the grid arrangement. According to another embodiment height of the ridge members may be lesser than the height of the grid arrangement 214. These arrangements at different heights provide uniform and controlled pressure on the transfer sandwich 128 when the transfer sandwich holder 100 is closed for the process of transferring the proteins from the gel member 140 to the membrane 138.

[0038] FIG. 4 illustrates a perspective view of the holding member 106 of the transfer sandwich holder 100 in accordance with an embodiment. The holding member 106 holds the transfer sandwich 128. The sponge member 132 is placed on an inner portion 400 of the holding member 106. The sponge member 132 is positioned on a grid arrangement 402 present in the holding member 106. The grid arrangement 402 is provided to allow essentially unrestricted fluidic and electrical contact with the transfer sandwich 128 in order to trigger transfer of the samples from the gel member 140 to the membrane 138. In an embodiment the grid arrangement 402 may be similar to the grid arrangement 214. Further when the transfer sandwich holder 100 is closed the covering member 102 and the holding member 106 are aligned in such a way that these grid arrangements are aligned in line. Further the sponge member 132 needs to be positioned in place within the holding member 106 hence slot members 404 and 406 are provided. The sponge member 132 gets seated between the slot members 404 and 406 to restrict its movement from its place. The transfer sandwich 128 is placed on the sponge member 132. The transfer sandwich 128 also needs to be secured in place which is achieved using one or more pin members i.e. an elongated pin 408 and a circular pin 410 (hereinafter collectively referred to as "pin members"). The elongated pin 408 and the circular pin 410 engage with slots provided in the transfer sandwich 128. As schematically illustrated in FIG. 5, a slot 412 and a slot 414 in the gel member 140 engages with the elongated pin 408 and the circular pin 410. The membrane 138 also includes a slot 416 and a slot 418 that engage with the elongated pin 408 and the circular pin 410 respectively as shown in FIG. 1. The slot 412 and the slot 416 may be oval in shape according to an embodiment to accommodate the elongated pin 408. Further the slot 414 and the slot 418 may be in round shape to accommodate a cylindrically shaped circular pin 410. More specifically the elongated pin 408 and the circular pin 410 pass through these slots to securely position the transfer sandwich 128. In an embodiment the elongated pin 408 and the circular pin 410 are configured at a position such that the transfer sandwich 128 is properly covered by the sponge members 130 and 132. Moreover the pin members and the slots in the gel member 140 and the membrane 138 may vary in size, shape and configuration in other embodiments. According to the disclosed embodiment, the slots 412, 414, 416 and 418 are compatible with or essentially identical with the pin members of the holding member. Further, like the slots 412 and 414 of the gel member 140, the slots 416 and 418 of the membrane 138 may be asymmetrical in a way that it can only be fitted into a complementary pin members of a holding member or the like in one single way, whereby, it cannot be inserted in the wrong way, upside down or the like.

[0039] A boundary member 420 is configured close to the pin members 408 and 410 to allow the transfer sandwich 128 to be conveniently positioned on the holding member 106. In one embodiment geometry of the boundary member 420 may match with shape and configuration of the transfer sandwich 128. In other exemplary embodiments different types of snapping or fastening arrangements may be provided in the holding member 106 to hold the transfer sandwich 128.

[0040] The holding member 106 includes guide ways i.e. the guide way 142 and the guide way 144 that allows the rolling member 104 to slide or roll along to roll over the transfer sandwich 128. The guide ways (e.g. the guide way 144) may protrude outside from a side wall of the holding member 106 as illustrated in FIG. 4. The guide ways may extend substantially throughout along the sidewalls of the holding member 106. In another embodiment the guide ways may be configured to extend only till halfway length of the sidewalls. In this case the rolling member can only move within guide ways till halfway length to roll over a transfer sandwich (as described in more detail below) which may extend only till the halfway length of the sidewalls. As explained earlier the covering member 102 needs to be removably fastened to the holding member 106 for closing the transfer sandwich holder 100. To achieve this, snapping members such as a snapping member 422 and a snapping member 424 are provided that engage with a slot 426 and a slot 428 respectively of the covering member 102. The snapping member enters a slot to be arranged as a lock. More specifically for instance the snapping member 422 passes through the slot 426 and a protruding member 430 gets snapped onto the slot 426 thereby fastening the covering member 102 to the holding member 106 as shown in FIG. 6. Similarly the snapping member 424 also has a protruding member 432 that snaps onto the slot 428. The snapping members are explained in accordance with one embodiment and it may be envisioned that other embodiments may have different kinds of fastening units for holding the covering member 102 and the holding member 106 in the closed position. When the transfer sandwich holder 100 is in the closed position the rolling member 104 may be positioned closer to a portion 434 of the holding member 106 as illustrated in FIG. 6.

[0041] Further when the transfer sandwich holder 100 is closed, in an embodiment side slits 436 and 438 (shown in FIG. 8) engages with the sidewalls of the holding member 106 in accordance with an embodiment. For instance a top edge portion 440 (shown in FIG. 4) of a side wall 148 engages with the side slit 438. In more detail, the top edge portion 440 is positioned within a gap of the slit 438.

[0042] Before closing the transfer sandwich holder 110, the transfer sandwich 128 is placed in the holding member 106. The transfer sandwich 128 needs to be rolled to allow any trapped air to escape out before performing the transfer process for separating the samples. To this end the covering member 102 is lifted using the holder 126. The coupling units 1 18 and 122 then engage with guide ways in the holding member 106 to facilitate movement of covering member 102 in a direction and/or orientation shown in arrow 'A' as shown in FIG. 9. For example the coupling unit 1 18 engages and moves along a guide way 142 as shown in FIG. 10. These coupling units 1 18 and 122 may slide or roll along their respective guide ways when the covering member 102 is moved. The guide ways are explained in detail above in conjunction with FIG. 4. Upon moving the covering member 102, the rolling member 104 rolls on the transfer sandwich 128 to apply pressure for removing the trapped air. In an embodiment the guide ways 142 and 144 are configured such a way that uniform pressure is applied on the transfer sandwich 128 at all areas where the rolling member 104 touches the transfer sandwich 128. The usage of the rolling member 104 makes it convenient for handling the transfer sandwich 128 without causing any damage to layers of the transfer sandwich 128. Referring back to structural configuration of the rolling members, the diameter and structural configuration may vary based on various factors namely but not limited to, thickness of a transfer sandwich (i.e. transfer sandwich), gel member material (for e.g. gradient gel and homogenous gel), sponge member material, density of the gel member material, and thickness of the gel member and the sponge member. The guide ways 142 and 144 may be preferably configured at a height from a base portion 146 of the holding member 106 to ensure uniform pressure is only applied on the transfer sandwich 128 as illustrated with a zoomed view in FIG. 10. Also due to the fixed height of the guide ways 142 and 144 only a fixed amount pressure can be applied on the transfer sandwich by any user when rolling. In another way these guide ways 142 and 144 may also ensure that more pressure is not applied due to user's fault thereby avoiding any damage or mishandling of the transfer sandwich 128. The guide ways 142 and 144 may not be provided completely throughout sidewalls 148 and 150 of the holding member 106 to prevent the coupling units 118 and 122 from sliding out of these guide ways. The length of the guide ways 142 and 144 may be provided such that the transfer sandwich 128 can be completely rolled accommodating its size. The guide ways 142 and 144 may be longer than the transfer sandwich 128 so that the rolling member 104 can roll to completely cover the transfer sandwich 128. It may be appreciated that the covering member 102 and the holding member 106 may be coupled with respect to each other using any other coupling arrangements. Besides, the guide ways for facilitating movement of the covering member 102 with respect to the holding member 106 is described herein according to one embodiment and thus may be envisioned that other movement facilitating arrangements may be configured to achieve rolling of a transfer sandwich.

[0043] After rolling the transfer sandwich 128, in order to close the transfer sandwich holder 100 the covering member 102 may be moved to allow the rolling member 104 reach the end portion 438 of the holding member 106. At the same occasion the coupling units 1 18 and 122 may also reach an end 152 of the guide way 142 and an end 154 of the guide way 144 respectively (with reference to FIG. 4, FIG. 5 and FIG. 10). The covering member 102 is then pivotally moved to close the transfer sandwich holder 100. The transfer sandwich 128 needs to be firmly held within the transfer sandwich holder 100. To an extent the sponge members 130 and 132 assist in firmly holding the transfer sandwich 128. The sponge members 130 and 132 may be comprised of any suitable material with appropriate material characteristics.

[0044] In another embodiment a holding member may have a supporting plane for allowing a rolling member (such as the rolling member 104) to move for rolling a transfer sandwich. As illustrated in FIG. 11 a holding member 1102 includes a supporting plane 1104 or track that allows the coupling unit 122 of the rolling member 104 to move from one end of the supporting plane 1 104 to another end. The supporting plane 1104 is provided at a side 1 106 of the holding member 1 102 similarly another supporting plane (not shown in figure) is provided at a side 1108 for the coupling unit 1 18 to move. These supporting planes allow the rolling member 104 to roll over the transfer sandwich (not shown in FIG. 1 1). The supporting planes such as the supporting plane 1104 may be configured at a particular height from a base portion 11 10 of the holding member 1 102 to ensure uniform pressure is only applied on the transfer sandwich when the rolling member 104 is rolled. Also due to the fixed height only a fixed amount pressure can be applied on the transfer sandwich by any user when rolling. While closing the transfer sandwich holder 1 100 using the covering member 102, the coupling units may fall into slots provided at the ends of the supporting planes. Considering the supporting plane 1104, a slot 11 12 is provided at the end of this plane. The slot 1 112 may be an 'L' shaped slot as illustrated in FIG. 11 according to an embodiment. When the rolling member 104 reaches the end of the supporting plane 1 104, the coupling unit 122 falls into the slot 1112 securely placing the rolling member 104 closer to a portion 1114 of the holding member 1 102. This also acts as a locking mechanism for locking the covering member 102 to the holding member 1 102 and keep in position. Moreover this mechanism also enables the rolling member 104 to be securely placed in the transfer sandwich holder 1 100.

[0045] During the transfer process the transfer sandwich holder 100 is placed in an electrolyte (in a solution or rigid form) and positioned between an anode and a cathode such that the covering member 102 is positioned proximal to the anode and the holding member 106 is positioned proximal to the cathode. When the transfer sandwich holder 100 is positioned within the electrolyte, a magnet holder 156 including a magnet 158 indicates that the transfer sandwich holder 100 is within a container having the buffer solution due to hall-effect. The electric field between the anode and cathode results in transfer of the samples such as proteins from the gel member 140 to the membrane 138. [0046] FIG. 12 and FIG. 13 schematically illustrate perspective views of an arrangement of a transfer sandwich that avoids any disarrangement of its layers in accordance with an exemplary embodiment. Typically the gel member needs to be placed first in the holding member 106 after keeping a filter pad. Thereafter a membrane is placed on top of the gel member followed by another filter pad which is already described in detail in conjunction with FIG. 1. When the user places the gel member and the membrane there is a possibility that membrane gets placed before the gel member. As illustrated in FIG. 12, a membrane 1200 is arranged with the support of a rigid frame 1202. A slot 1204 having an opening member 1206 is provided in the rigid frame 1202. The slot 1204 and the opening member 1206 is shown to be rectangular shape, however they may have any other convenient shape. In an embodiment the opening member 1206 may be formed by cutting a portion of the rigid frame of 1202 of the membrane 1200. In another embodiment the opening member 1206 may be movably coupled to an edge 1208 of the slot 1204. For example the opening member 1206 may be hinged to the edge 1208. Also it may be envisioned that the opening member 1206 may be coupled to the edge 1208 using any other arrangements such that when the membrane 1200 is placed on the holding member 106, the circular pin 410 moves through the slot 1204 to push the opening member 1206. Thereafter when the gel member 140 having the slot 414 is placed on the holding member 106, the way through which the circular pin 410 needs to pass through the slot 1204 is obstructed by the opening member 1108. Consequently the gel member 140 cannot be placed on the membrane 1200. This indicates that the order of arrangement of the gel member 140 and the membrane 1200 is incorrect. So the user can remove the membrane 1200 and assemble the gel member 140 first followed by the membrane 138.

[0047] Even when the gel member 140 and the membrane 1200 are correctly placed, the opening member 1206 may be push opened by the circular pin 410 when it passes through the slot 1204. The opening member 1206 is accommodated within an aperture 1210 in a covering member 1400 as shown in FIG. 14. The aperture 1210 has a larger size as compared to the slot 1204 so as to accommodate the opening member 1206. The aperture 1210 may have a rectangular shape so that the opening member 1206 passes through it in an open position.

[0048] Now referring to the structure of the transfer sandwich holder 100, the transfer sandwich holder 100 including the covering member 102 and the holding member 106 need to have a rigid structure for storage and use and hence needs to be made of rigid material. Moreover, as disclosed in detail above, the transfer sandwich holder 100 is designed for running electrophoretic separation, therefore the covering member 102 and the holding member 106 should be electrically insulating.

[0049] The transfer sandwich holder with the rolling member coupled to the covering member facilitates in convenient rolling for preparation of the transfer sandwich for the transfer process. A user can conveniently hold the covering member in an orientation and roll the rolling member over the transfer sandwich to remove the trapped air. As the guide ways are also positioned at a particular height to facilitate the rolling of the rolling member uniform and optimum pressure is only applied on the transfer sandwich. Even if the user does put more pressure the guide ways restrict the movement of the roller in a direction perpendicular to the transfer sandwich thereby avoiding any application of extra pressure on the transfer sandwich.

[0050] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any computing system or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

We Claim:

1. A transfer sandwich holder comprising:

a covering member;

at least one rolling member coupled to an end portion of the covering member; and

a holding member for holding a transfer sandwich, wherein a rolling member is movably configured with respect to the holding member for rolling on the transfer sandwich, wherein the covering member is arranged with respect to the holding member for opening and closing the transfer sandwich holder.

2. The transfer sandwich holder according to claim 1 further comprises a plurality of coupling units, wherein coupling units couple a rolling member of the plurality of rolling members to the end portion of the covering member.

3. The transfer sandwich holder according to claim 2, wherein the coupling units are further configured to pivotally arrange the covering member with respect to the holding member for opening and closing the transfer sandwich holder.

4. The transfer sandwich holder according to claim 2, wherein the holding member comprises a plurality of guide ways, the coupling units move through guideways for enabling the rolling member to roll on the transfer sandwich when the covering member is at a position for opening the transfer sandwich holder.

5. The transfer sandwich holder according to claim 4, wherein the covering member comprises a holder for opening and closing the transfer sandwich holder and a user holds the holder to move the covering member for rolling the rolling member on the transfer sandwich.

6. The transfer sandwich holder according to claim 2, wherein each coupling unit have different configuration to ensure orientation of the covering member while arranged with respect to the holding member.

7. The transfer sandwich holder according to claim 1 , wherein a rolling member of the at least one rolling member is a cylindrical rolling member.

8. The transfer sandwich holder according to claim 1 further comprises a plurality of sponge members, wherein a first sponge member is arranged at an inner portion of the holding member and a second sponge member is arranged at an inner portion of the covering member.

9. The transfer sandwich holder according to claim 8, wherein the covering member comprises a grid arrangement having the first sponge member positioned proximal to its one side.

10. The transfer sandwich holder according to claim 1 , wherein the holding member comprises at least one snapping member and the covering member comprises at least one snap receiver for engaging with the at least one snapping member to close the transfer sandwich holder.

1 1. The transfer sandwich holder according to claim 10, wherein the transfer sandwich comprises a gel member and a membrane, wherein the gel member comprises at least one slot that engages with a snapping member of the at least one snapping member, and wherein the membrane comprise at least one slot that engages with a snapping member of the at least one snapping member to position the transfer sandwich in the holding member.

12. The transfer sandwich holder according to claim 11 , wherein the membrane comprise an opening member for opening and closing a slot in the membrane, the opening member opens upon a snapping member of the holding member passes through the slot of the membrane.

13. The transfer sandwich holder according to claim 12, wherein when the gel member is positioned over the membrane in the holding member the opening member in an opened position obstruct the snapping member from passing through a slot in the gel member indicating error in order of arrangement of the membrane and the gel member in holding member, the slot in the gel member is smaller than the slot in the membrane.

14. The transfer sandwich holder according to claim 1 1 , wherein the covering member comprises an aperture enabling the opening member to pass through in an open position when the transfer sandwich holder is closed.